"Your president leads the world in the cause of freedom right now ... The people of Ukraine are not just fighting for your own freedom, you're fighting for all of us who love freedom," Bono told a crowd of up to 100 gathered inside the Khreshchatyk metro station.
He was referring to Ukrainian President Volodymyr Zelenskiy. Russia invaded Ukraine on February 24, pressing towards Kyiv before withdrawing its forces from near the capital at the end of March to concentrate its firepower on eastern Ukraine.
Russia, which calls its action in Ukraine a "special military operation", continues to carry out missile strikes across Ukraine. However, some life has returned to Kyiv even though air raid sirens sound regularly.
Bono rallied the crowd between songs during his performance.
"This evening, 8th of May, shots will ring out in the Ukraine sky, but you'll be free at last. They can take your lives, but they can never take your pride," he said.